This invention relates to a molding machine for semiconductor package. It particularly relates to a molding machine having a port for compressive resin, which can mold a semiconductor package whether the port is located on a top side of the mold or on a bottom side of the mold.
Generally, a molding machine for semiconductor package molds resin-compound into a leadframe of a semiconductor after finishing a wire bonding and a die bonding, so as to protect the welding of the leadframe and a semiconductor chip.
Conventionally, a molding machine comprises a guiding rod (10), a top plate (11) fixed on an end of the rod (10), a moving plate (12) moving along the rod (10), a mold (13) between the top plate (11) and the moving plate (12), a transfer-rod (18) having a flanger tip (17) for pressing resin (16) into the leadframe (15) fed into the mold (13) and a hydraulic cylinder (14) moving the transfer-rod (18) as shown in FIG. 3 and 4.
Accordingly, the moving plate (12) is raised along the guiding rod (10), so to the upper mold (19) and the lower mold (20) is closed, and supplies resin (16), to be preheated, into a port (23) via an inlet (24) for resin (24) formed between the upper mold (19) and the top plate (11). Then a molding of a semiconductor package is accomplished while resin (16) in the port (16) wrap around a semiconductor chip arranged in a cavity block (21) via a runner formed in a runner block (22), when the flanger tip (17) of the transfer-rod (18) is moving downward (as shown in FIGS. 4(A) and 4(B)).
In the foregoing process of molding, when the resin (16) is fed to the semiconductor chip via the inlet (24) and the port (23), resin (16) for molding of the semiconductor chip should be supplied to the port (23) while the flanger tip (17) of the transfer-rod (18) is completely free from the inlet (24) formed between the upper mold (19) and the top plate (11). Consequently, since a stroke of the flanger tip (17) is long, the molding productivity is decreased. Also since an air layer between resin (16) and the flanger tip (17) is long, blowholes are frequently formed in the package and/or a wire connecting the lead and the chip bends.
Furthermore, since resin (16) is inserted into an aperture formed by a difference of temperature between the port (23) and the flanger tip (17), abrasion between the port (23) and the flanger tip (17) is increased, and sometimes it may cause the molding machine to stop operating.
In view of the foregoing, considerable effort has been expended to provide a molding machine for a semiconductor package that may produce an accurate semiconductor package.
For example, a molding machine may comprise a hydraulic cylinder (14) that is selectively run by a controller (not shown) in the bottom part of the moving plate (12); a transfer-rod (2) that is moved upwardly by the hydraulic cylinder (1); and a flanger tip (5) may compress resin (16) that is filled in the port about half degree, in which the port arranged in the lower mold (20). In such molding machine, the problem exists that the molding machine having a transfer-rod in the top portion and the molding machine having a transfer-rod in the bottom portion is required since the flanger tip (17) supplies resin into the mold when moving downward in the conventional mold. Consequently, it is inconvenient in purchase, manufacturing and installation, since 2 types of molding machines having different way of transfer are needed.